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iter_utils.c
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iter_utils.c
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/*
* iterator/iter_utils.c - iterative resolver module utility functions.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains functions to assist the iterator module.
* Configuration options. Forward zones.
*/
#include "config.h"
#include "iterator/iter_utils.h"
#include "iterator/iterator.h"
#include "iterator/iter_hints.h"
#include "iterator/iter_fwd.h"
#include "iterator/iter_donotq.h"
#include "iterator/iter_delegpt.h"
#include "iterator/iter_priv.h"
#include "services/cache/infra.h"
#include "services/cache/dns.h"
#include "services/cache/rrset.h"
#include "services/outside_network.h"
#include "util/net_help.h"
#include "util/module.h"
#include "util/log.h"
#include "util/config_file.h"
#include "util/regional.h"
#include "util/data/msgparse.h"
#include "util/data/dname.h"
#include "util/random.h"
#include "util/fptr_wlist.h"
#include "validator/val_anchor.h"
#include "validator/val_kcache.h"
#include "validator/val_kentry.h"
#include "validator/val_utils.h"
#include "validator/val_sigcrypt.h"
#include "sldns/sbuffer.h"
#include "sldns/str2wire.h"
/** time when nameserver glue is said to be 'recent' */
#define SUSPICION_RECENT_EXPIRY 86400
/** if NAT64 is enabled and no NAT64 prefix is configured, first fall back to
* DNS64 prefix. If that is not configured, fall back to this default value.
*/
static const char DEFAULT_NAT64_PREFIX[] = "64:ff9b::/96";
/** fillup fetch policy array */
static void
fetch_fill(struct iter_env* ie, const char* str)
{
char* s = (char*)str, *e;
int i;
for(i=0; i<ie->max_dependency_depth+1; i++) {
ie->target_fetch_policy[i] = strtol(s, &e, 10);
if(s == e)
fatal_exit("cannot parse fetch policy number %s", s);
s = e;
}
}
/** Read config string that represents the target fetch policy */
static int
read_fetch_policy(struct iter_env* ie, const char* str)
{
int count = cfg_count_numbers(str);
if(count < 1) {
log_err("Cannot parse target fetch policy: \"%s\"", str);
return 0;
}
ie->max_dependency_depth = count - 1;
ie->target_fetch_policy = (int*)calloc(
(size_t)ie->max_dependency_depth+1, sizeof(int));
if(!ie->target_fetch_policy) {
log_err("alloc fetch policy: out of memory");
return 0;
}
fetch_fill(ie, str);
return 1;
}
/** apply config caps whitelist items to name tree */
static int
caps_white_apply_cfg(rbtree_type* ntree, struct config_file* cfg)
{
struct config_strlist* p;
for(p=cfg->caps_whitelist; p; p=p->next) {
struct name_tree_node* n;
size_t len;
uint8_t* nm = sldns_str2wire_dname(p->str, &len);
if(!nm) {
log_err("could not parse %s", p->str);
return 0;
}
n = (struct name_tree_node*)calloc(1, sizeof(*n));
if(!n) {
log_err("out of memory");
free(nm);
return 0;
}
n->node.key = n;
n->name = nm;
n->len = len;
n->labs = dname_count_labels(nm);
n->dclass = LDNS_RR_CLASS_IN;
if(!name_tree_insert(ntree, n, nm, len, n->labs, n->dclass)) {
/* duplicate element ignored, idempotent */
free(n->name);
free(n);
}
}
name_tree_init_parents(ntree);
return 1;
}
int
iter_apply_cfg(struct iter_env* iter_env, struct config_file* cfg)
{
const char *nat64_prefix;
int i;
/* target fetch policy */
if(!read_fetch_policy(iter_env, cfg->target_fetch_policy))
return 0;
for(i=0; i<iter_env->max_dependency_depth+1; i++)
verbose(VERB_QUERY, "target fetch policy for level %d is %d",
i, iter_env->target_fetch_policy[i]);
if(!iter_env->donotq)
iter_env->donotq = donotq_create();
if(!iter_env->donotq || !donotq_apply_cfg(iter_env->donotq, cfg)) {
log_err("Could not set donotqueryaddresses");
return 0;
}
if(!iter_env->priv)
iter_env->priv = priv_create();
if(!iter_env->priv || !priv_apply_cfg(iter_env->priv, cfg)) {
log_err("Could not set private addresses");
return 0;
}
if(cfg->caps_whitelist) {
if(!iter_env->caps_white)
iter_env->caps_white = rbtree_create(name_tree_compare);
if(!iter_env->caps_white || !caps_white_apply_cfg(
iter_env->caps_white, cfg)) {
log_err("Could not set capsforid whitelist");
return 0;
}
}
nat64_prefix = cfg->nat64_prefix;
if (!nat64_prefix)
nat64_prefix = cfg->dns64_prefix;
if (!nat64_prefix)
nat64_prefix = DEFAULT_NAT64_PREFIX;
if (!netblockstrtoaddr(nat64_prefix, 0, &iter_env->nat64_prefix_addr,
&iter_env->nat64_prefix_addrlen,
&iter_env->nat64_prefix_net)) {
log_err("cannot parse nat64-prefix netblock: %s", nat64_prefix);
return 0;
}
if (!addr_is_ip6(&iter_env->nat64_prefix_addr,
iter_env->nat64_prefix_addrlen)) {
log_err("nat64_prefix is not IPv6: %s", cfg->nat64_prefix);
return 0;
}
if (iter_env->nat64_prefix_net != 32 && iter_env->nat64_prefix_net != 40 &&
iter_env->nat64_prefix_net != 48 && iter_env->nat64_prefix_net != 56 &&
iter_env->nat64_prefix_net != 64 && iter_env->nat64_prefix_net != 96 ) {
log_err("dns64-prefix length it not 32, 40, 48, 56, 64 or 96: %s",
nat64_prefix);
return 0;
}
iter_env->supports_ipv6 = cfg->do_ip6;
iter_env->supports_ipv4 = cfg->do_ip4;
iter_env->use_nat64 = cfg->do_nat64;
iter_env->outbound_msg_retry = cfg->outbound_msg_retry;
return 1;
}
/** filter out unsuitable targets
* @param iter_env: iterator environment with ipv6-support flag.
* @param env: module environment with infra cache.
* @param name: zone name
* @param namelen: length of name
* @param qtype: query type (host order).
* @param now: current time
* @param a: address in delegation point we are examining.
* @return an integer that signals the target suitability.
* as follows:
* -1: The address should be omitted from the list.
* Because:
* o The address is bogus (DNSSEC validation failure).
* o Listed as donotquery
* o is ipv6 but no ipv6 support (in operating system).
* o is ipv4 but no ipv4 support (in operating system).
* o is lame
* Otherwise, an rtt in milliseconds.
* 0 .. USEFUL_SERVER_TOP_TIMEOUT-1
* The roundtrip time timeout estimate. less than 2 minutes.
* Note that util/rtt.c has a MIN_TIMEOUT of 50 msec, thus
* values 0 .. 49 are not used, unless that is changed.
* USEFUL_SERVER_TOP_TIMEOUT
* This value exactly is given for unresponsive blacklisted.
* USEFUL_SERVER_TOP_TIMEOUT+1
* For non-blacklisted servers: huge timeout, but has traffic.
* USEFUL_SERVER_TOP_TIMEOUT*1 ..
* parent-side lame servers get this penalty. A dispreferential
* server. (lame in delegpt).
* USEFUL_SERVER_TOP_TIMEOUT*2 ..
* dnsseclame servers get penalty
* USEFUL_SERVER_TOP_TIMEOUT*3 ..
* recursion lame servers get penalty
* UNKNOWN_SERVER_NICENESS
* If no information is known about the server, this is
* returned. 376 msec or so.
* +BLACKLIST_PENALTY (of USEFUL_TOP_TIMEOUT*4) for dnssec failed IPs.
*
* When a final value is chosen that is dnsseclame ; dnsseclameness checking
* is turned off (so we do not discard the reply).
* When a final value is chosen that is recursionlame; RD bit is set on query.
* Because of the numbers this means recursionlame also have dnssec lameness
* checking turned off.
*/
static int
iter_filter_unsuitable(struct iter_env* iter_env, struct module_env* env,
uint8_t* name, size_t namelen, uint16_t qtype, time_t now,
struct delegpt_addr* a)
{
int rtt, lame, reclame, dnsseclame;
if(a->bogus)
return -1; /* address of server is bogus */
if(donotq_lookup(iter_env->donotq, &a->addr, a->addrlen)) {
log_addr(VERB_ALGO, "skip addr on the donotquery list",
&a->addr, a->addrlen);
return -1; /* server is on the donotquery list */
}
if(!iter_env->supports_ipv6 && addr_is_ip6(&a->addr, a->addrlen)) {
return -1; /* there is no ip6 available */
}
if(!iter_env->supports_ipv4 && !iter_env->use_nat64 &&
!addr_is_ip6(&a->addr, a->addrlen)) {
return -1; /* there is no ip4 available */
}
/* check lameness - need zone , class info */
if(infra_get_lame_rtt(env->infra_cache, &a->addr, a->addrlen,
name, namelen, qtype, &lame, &dnsseclame, &reclame,
&rtt, now)) {
log_addr(VERB_ALGO, "servselect", &a->addr, a->addrlen);
verbose(VERB_ALGO, " rtt=%d%s%s%s%s", rtt,
lame?" LAME":"",
dnsseclame?" DNSSEC_LAME":"",
reclame?" REC_LAME":"",
a->lame?" ADDR_LAME":"");
if(lame)
return -1; /* server is lame */
else if(rtt >= USEFUL_SERVER_TOP_TIMEOUT)
/* server is unresponsive,
* we used to return TOP_TIMEOUT, but fairly useless,
* because if == TOP_TIMEOUT is dropped because
* blacklisted later, instead, remove it here, so
* other choices (that are not blacklisted) can be
* tried */
return -1;
/* select remainder from worst to best */
else if(reclame)
return rtt+USEFUL_SERVER_TOP_TIMEOUT*3; /* nonpref */
else if(dnsseclame || a->dnsseclame)
return rtt+USEFUL_SERVER_TOP_TIMEOUT*2; /* nonpref */
else if(a->lame)
return rtt+USEFUL_SERVER_TOP_TIMEOUT+1; /* nonpref */
else return rtt;
}
/* no server information present */
if(a->dnsseclame)
return UNKNOWN_SERVER_NICENESS+USEFUL_SERVER_TOP_TIMEOUT*2; /* nonpref */
else if(a->lame)
return USEFUL_SERVER_TOP_TIMEOUT+1+UNKNOWN_SERVER_NICENESS; /* nonpref */
return UNKNOWN_SERVER_NICENESS;
}
/** lookup RTT information, and also store fastest rtt (if any) */
static int
iter_fill_rtt(struct iter_env* iter_env, struct module_env* env,
uint8_t* name, size_t namelen, uint16_t qtype, time_t now,
struct delegpt* dp, int* best_rtt, struct sock_list* blacklist,
size_t* num_suitable_results)
{
int got_it = 0;
struct delegpt_addr* a;
*num_suitable_results = 0;
if(dp->bogus)
return 0; /* NS bogus, all bogus, nothing found */
for(a=dp->result_list; a; a = a->next_result) {
a->sel_rtt = iter_filter_unsuitable(iter_env, env,
name, namelen, qtype, now, a);
if(a->sel_rtt != -1) {
if(sock_list_find(blacklist, &a->addr, a->addrlen))
a->sel_rtt += BLACKLIST_PENALTY;
if(!got_it) {
*best_rtt = a->sel_rtt;
got_it = 1;
} else if(a->sel_rtt < *best_rtt) {
*best_rtt = a->sel_rtt;
}
(*num_suitable_results)++;
}
}
return got_it;
}
/** compare two rtts, return -1, 0 or 1 */
static int
rtt_compare(const void* x, const void* y)
{
if(*(int*)x == *(int*)y)
return 0;
if(*(int*)x > *(int*)y)
return 1;
return -1;
}
/** get RTT for the Nth fastest server */
static int
nth_rtt(struct delegpt_addr* result_list, size_t num_results, size_t n)
{
int rtt_band;
size_t i;
int* rtt_list, *rtt_index;
if(num_results < 1 || n >= num_results) {
return -1;
}
rtt_list = calloc(num_results, sizeof(int));
if(!rtt_list) {
log_err("malloc failure: allocating rtt_list");
return -1;
}
rtt_index = rtt_list;
for(i=0; i<num_results && result_list; i++) {
if(result_list->sel_rtt != -1) {
*rtt_index = result_list->sel_rtt;
rtt_index++;
}
result_list=result_list->next_result;
}
qsort(rtt_list, num_results, sizeof(*rtt_list), rtt_compare);
log_assert(n > 0);
rtt_band = rtt_list[n-1];
free(rtt_list);
return rtt_band;
}
/** filter the address list, putting best targets at front,
* returns number of best targets (or 0, no suitable targets) */
static int
iter_filter_order(struct iter_env* iter_env, struct module_env* env,
uint8_t* name, size_t namelen, uint16_t qtype, time_t now,
struct delegpt* dp, int* selected_rtt, int open_target,
struct sock_list* blacklist, time_t prefetch)
{
int got_num = 0, low_rtt = 0, swap_to_front, rtt_band = RTT_BAND, nth;
int alllame = 0;
size_t num_results;
struct delegpt_addr* a, *n, *prev=NULL;
/* fillup sel_rtt and find best rtt in the bunch */
got_num = iter_fill_rtt(iter_env, env, name, namelen, qtype, now, dp,
&low_rtt, blacklist, &num_results);
if(got_num == 0)
return 0;
if(low_rtt >= USEFUL_SERVER_TOP_TIMEOUT &&
/* If all missing (or not fully resolved) targets are lame,
* then use the remaining lame address. */
((delegpt_count_missing_targets(dp, &alllame) > 0 && !alllame) ||
open_target > 0)) {
verbose(VERB_ALGO, "Bad choices, trying to get more choice");
return 0; /* we want more choice. The best choice is a bad one.
return 0 to force the caller to fetch more */
}
if(env->cfg->fast_server_permil != 0 && prefetch == 0 &&
num_results > env->cfg->fast_server_num &&
ub_random_max(env->rnd, 1000) < env->cfg->fast_server_permil) {
/* the query is not prefetch, but for a downstream client,
* there are more servers available then the fastest N we want
* to choose from. Limit our choice to the fastest servers. */
nth = nth_rtt(dp->result_list, num_results,
env->cfg->fast_server_num);
if(nth > 0) {
rtt_band = nth - low_rtt;
if(rtt_band > RTT_BAND)
rtt_band = RTT_BAND;
}
}
got_num = 0;
a = dp->result_list;
while(a) {
/* skip unsuitable targets */
if(a->sel_rtt == -1) {
prev = a;
a = a->next_result;
continue;
}
/* classify the server address and determine what to do */
swap_to_front = 0;
if(a->sel_rtt >= low_rtt && a->sel_rtt - low_rtt <= rtt_band) {
got_num++;
swap_to_front = 1;
} else if(a->sel_rtt<low_rtt && low_rtt-a->sel_rtt<=rtt_band) {
got_num++;
swap_to_front = 1;
}
/* swap to front if necessary, or move to next result */
if(swap_to_front && prev) {
n = a->next_result;
prev->next_result = n;
a->next_result = dp->result_list;
dp->result_list = a;
a = n;
} else {
prev = a;
a = a->next_result;
}
}
*selected_rtt = low_rtt;
if (env->cfg->prefer_ip6) {
int got_num6 = 0;
int low_rtt6 = 0;
int i;
int attempt = -1; /* filter to make sure addresses have
less attempts on them than the first, to force round
robin when all the IPv6 addresses fail */
int num4ok = 0; /* number ip4 at low attempt count */
int num4_lowrtt = 0;
prev = NULL;
a = dp->result_list;
for(i = 0; i < got_num; i++) {
if(!a) break; /* robustness */
swap_to_front = 0;
if(a->addr.ss_family != AF_INET6 && attempt == -1) {
/* if we only have ip4 at low attempt count,
* then ip6 is failing, and we need to
* select one of the remaining IPv4 addrs */
attempt = a->attempts;
num4ok++;
num4_lowrtt = a->sel_rtt;
} else if(a->addr.ss_family != AF_INET6 && attempt == a->attempts) {
num4ok++;
if(num4_lowrtt == 0 || a->sel_rtt < num4_lowrtt) {
num4_lowrtt = a->sel_rtt;
}
}
if(a->addr.ss_family == AF_INET6) {
if(attempt == -1) {
attempt = a->attempts;
} else if(a->attempts > attempt) {
break;
}
got_num6++;
swap_to_front = 1;
if(low_rtt6 == 0 || a->sel_rtt < low_rtt6) {
low_rtt6 = a->sel_rtt;
}
}
/* swap to front if IPv6, or move to next result */
if(swap_to_front && prev) {
n = a->next_result;
prev->next_result = n;
a->next_result = dp->result_list;
dp->result_list = a;
a = n;
} else {
prev = a;
a = a->next_result;
}
}
if(got_num6 > 0) {
got_num = got_num6;
*selected_rtt = low_rtt6;
} else if(num4ok > 0) {
got_num = num4ok;
*selected_rtt = num4_lowrtt;
}
} else if (env->cfg->prefer_ip4) {
int got_num4 = 0;
int low_rtt4 = 0;
int i;
int attempt = -1; /* filter to make sure addresses have
less attempts on them than the first, to force round
robin when all the IPv4 addresses fail */
int num6ok = 0; /* number ip6 at low attempt count */
int num6_lowrtt = 0;
prev = NULL;
a = dp->result_list;
for(i = 0; i < got_num; i++) {
if(!a) break; /* robustness */
swap_to_front = 0;
if(a->addr.ss_family != AF_INET && attempt == -1) {
/* if we only have ip6 at low attempt count,
* then ip4 is failing, and we need to
* select one of the remaining IPv6 addrs */
attempt = a->attempts;
num6ok++;
num6_lowrtt = a->sel_rtt;
} else if(a->addr.ss_family != AF_INET && attempt == a->attempts) {
num6ok++;
if(num6_lowrtt == 0 || a->sel_rtt < num6_lowrtt) {
num6_lowrtt = a->sel_rtt;
}
}
if(a->addr.ss_family == AF_INET) {
if(attempt == -1) {
attempt = a->attempts;
} else if(a->attempts > attempt) {
break;
}
got_num4++;
swap_to_front = 1;
if(low_rtt4 == 0 || a->sel_rtt < low_rtt4) {
low_rtt4 = a->sel_rtt;
}
}
/* swap to front if IPv4, or move to next result */
if(swap_to_front && prev) {
n = a->next_result;
prev->next_result = n;
a->next_result = dp->result_list;
dp->result_list = a;
a = n;
} else {
prev = a;
a = a->next_result;
}
}
if(got_num4 > 0) {
got_num = got_num4;
*selected_rtt = low_rtt4;
} else if(num6ok > 0) {
got_num = num6ok;
*selected_rtt = num6_lowrtt;
}
}
return got_num;
}
struct delegpt_addr*
iter_server_selection(struct iter_env* iter_env,
struct module_env* env, struct delegpt* dp,
uint8_t* name, size_t namelen, uint16_t qtype, int* dnssec_lame,
int* chase_to_rd, int open_target, struct sock_list* blacklist,
time_t prefetch)
{
int sel;
int selrtt;
struct delegpt_addr* a, *prev;
int num = iter_filter_order(iter_env, env, name, namelen, qtype,
*env->now, dp, &selrtt, open_target, blacklist, prefetch);
if(num == 0)
return NULL;
verbose(VERB_ALGO, "selrtt %d", selrtt);
if(selrtt > BLACKLIST_PENALTY) {
if(selrtt-BLACKLIST_PENALTY > USEFUL_SERVER_TOP_TIMEOUT*3) {
verbose(VERB_ALGO, "chase to "
"blacklisted recursion lame server");
*chase_to_rd = 1;
}
if(selrtt-BLACKLIST_PENALTY > USEFUL_SERVER_TOP_TIMEOUT*2) {
verbose(VERB_ALGO, "chase to "
"blacklisted dnssec lame server");
*dnssec_lame = 1;
}
} else {
if(selrtt > USEFUL_SERVER_TOP_TIMEOUT*3) {
verbose(VERB_ALGO, "chase to recursion lame server");
*chase_to_rd = 1;
}
if(selrtt > USEFUL_SERVER_TOP_TIMEOUT*2) {
verbose(VERB_ALGO, "chase to dnssec lame server");
*dnssec_lame = 1;
}
if(selrtt == USEFUL_SERVER_TOP_TIMEOUT) {
verbose(VERB_ALGO, "chase to blacklisted lame server");
return NULL;
}
}
if(num == 1) {
a = dp->result_list;
if(++a->attempts < iter_env->outbound_msg_retry)
return a;
dp->result_list = a->next_result;
return a;
}
/* randomly select a target from the list */
log_assert(num > 1);
/* grab secure random number, to pick unexpected server.
* also we need it to be threadsafe. */
sel = ub_random_max(env->rnd, num);
a = dp->result_list;
prev = NULL;
while(sel > 0 && a) {
prev = a;
a = a->next_result;
sel--;
}
if(!a) /* robustness */
return NULL;
if(++a->attempts < iter_env->outbound_msg_retry)
return a;
/* remove it from the delegation point result list */
if(prev)
prev->next_result = a->next_result;
else dp->result_list = a->next_result;
return a;
}
struct dns_msg*
dns_alloc_msg(sldns_buffer* pkt, struct msg_parse* msg,
struct regional* region)
{
struct dns_msg* m = (struct dns_msg*)regional_alloc(region,
sizeof(struct dns_msg));
if(!m)
return NULL;
memset(m, 0, sizeof(*m));
if(!parse_create_msg(pkt, msg, NULL, &m->qinfo, &m->rep, region)) {
log_err("malloc failure: allocating incoming dns_msg");
return NULL;
}
return m;
}
struct dns_msg*
dns_copy_msg(struct dns_msg* from, struct regional* region)
{
struct dns_msg* m = (struct dns_msg*)regional_alloc(region,
sizeof(struct dns_msg));
if(!m)
return NULL;
m->qinfo = from->qinfo;
if(!(m->qinfo.qname = regional_alloc_init(region, from->qinfo.qname,
from->qinfo.qname_len)))
return NULL;
if(!(m->rep = reply_info_copy(from->rep, NULL, region)))
return NULL;
return m;
}
void
iter_dns_store(struct module_env* env, struct query_info* msgqinf,
struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
struct regional* region, uint16_t flags, time_t qstarttime)
{
if(!dns_cache_store(env, msgqinf, msgrep, is_referral, leeway,
pside, region, flags, qstarttime))
log_err("out of memory: cannot store data in cache");
}
int
iter_ns_probability(struct ub_randstate* rnd, int n, int m)
{
int sel;
if(n == m) /* 100% chance */
return 1;
/* we do not need secure random numbers here, but
* we do need it to be threadsafe, so we use this */
sel = ub_random_max(rnd, m);
return (sel < n);
}
/** detect dependency cycle for query and target */
static int
causes_cycle(struct module_qstate* qstate, uint8_t* name, size_t namelen,
uint16_t t, uint16_t c)
{
struct query_info qinf;
qinf.qname = name;
qinf.qname_len = namelen;
qinf.qtype = t;
qinf.qclass = c;
qinf.local_alias = NULL;
fptr_ok(fptr_whitelist_modenv_detect_cycle(
qstate->env->detect_cycle));
return (*qstate->env->detect_cycle)(qstate, &qinf,
(uint16_t)(BIT_RD|BIT_CD), qstate->is_priming,
qstate->is_valrec);
}
void
iter_mark_cycle_targets(struct module_qstate* qstate, struct delegpt* dp)
{
struct delegpt_ns* ns;
for(ns = dp->nslist; ns; ns = ns->next) {
if(ns->resolved)
continue;
/* see if this ns as target causes dependency cycle */
if(causes_cycle(qstate, ns->name, ns->namelen,
LDNS_RR_TYPE_AAAA, qstate->qinfo.qclass) ||
causes_cycle(qstate, ns->name, ns->namelen,
LDNS_RR_TYPE_A, qstate->qinfo.qclass)) {
log_nametypeclass(VERB_QUERY, "skipping target due "
"to dependency cycle (harden-glue: no may "
"fix some of the cycles)",
ns->name, LDNS_RR_TYPE_A,
qstate->qinfo.qclass);
ns->resolved = 1;
}
}
}
void
iter_mark_pside_cycle_targets(struct module_qstate* qstate, struct delegpt* dp)
{
struct delegpt_ns* ns;
for(ns = dp->nslist; ns; ns = ns->next) {
if(ns->done_pside4 && ns->done_pside6)
continue;
/* see if this ns as target causes dependency cycle */
if(causes_cycle(qstate, ns->name, ns->namelen,
LDNS_RR_TYPE_A, qstate->qinfo.qclass)) {
log_nametypeclass(VERB_QUERY, "skipping target due "
"to dependency cycle", ns->name,
LDNS_RR_TYPE_A, qstate->qinfo.qclass);
ns->done_pside4 = 1;
}
if(causes_cycle(qstate, ns->name, ns->namelen,
LDNS_RR_TYPE_AAAA, qstate->qinfo.qclass)) {
log_nametypeclass(VERB_QUERY, "skipping target due "
"to dependency cycle", ns->name,
LDNS_RR_TYPE_AAAA, qstate->qinfo.qclass);
ns->done_pside6 = 1;
}
}
}
int
iter_dp_is_useless(struct query_info* qinfo, uint16_t qflags,
struct delegpt* dp, int supports_ipv4, int supports_ipv6, int use_nat64)
{
struct delegpt_ns* ns;
struct delegpt_addr* a;
if (supports_ipv6 && use_nat64)
supports_ipv4 = 1;
/* check:
* o RD qflag is on.
* o no addresses are provided.
* o all NS items are required glue.
* OR
* o RD qflag is on.
* o no addresses are provided.
* o the query is for one of the nameservers in dp,
* and that nameserver is a glue-name for this dp.
*/
if(!(qflags&BIT_RD))
return 0;
/* either available or unused targets,
* if they exist, the dp is not useless. */
for(a = dp->usable_list; a; a = a->next_usable) {
if(!addr_is_ip6(&a->addr, a->addrlen) && supports_ipv4)
return 0;
else if(addr_is_ip6(&a->addr, a->addrlen) && supports_ipv6)
return 0;
}
for(a = dp->result_list; a; a = a->next_result) {
if(!addr_is_ip6(&a->addr, a->addrlen) && supports_ipv4)
return 0;
else if(addr_is_ip6(&a->addr, a->addrlen) && supports_ipv6)
return 0;
}
/* see if query is for one of the nameservers, which is glue */
if( ((qinfo->qtype == LDNS_RR_TYPE_A && supports_ipv4) ||
(qinfo->qtype == LDNS_RR_TYPE_AAAA && supports_ipv6)) &&
dname_subdomain_c(qinfo->qname, dp->name) &&
delegpt_find_ns(dp, qinfo->qname, qinfo->qname_len))
return 1;
for(ns = dp->nslist; ns; ns = ns->next) {
if(ns->resolved) /* skip failed targets */
continue;
if(!dname_subdomain_c(ns->name, dp->name))
return 0; /* one address is not required glue */
}
return 1;
}
int
iter_qname_indicates_dnssec(struct module_env* env, struct query_info *qinfo)
{
struct trust_anchor* a;
if(!env || !env->anchors || !qinfo || !qinfo->qname)
return 0;
/* a trust anchor exists above the name? */
if((a=anchors_lookup(env->anchors, qinfo->qname, qinfo->qname_len,
qinfo->qclass))) {
if(a->numDS == 0 && a->numDNSKEY == 0) {
/* insecure trust point */
lock_basic_unlock(&a->lock);
return 0;
}
lock_basic_unlock(&a->lock);
return 1;
}
/* no trust anchor above it. */
return 0;
}
int
iter_indicates_dnssec(struct module_env* env, struct delegpt* dp,
struct dns_msg* msg, uint16_t dclass)
{
struct trust_anchor* a;
/* information not available, !env->anchors can be common */
if(!env || !env->anchors || !dp || !dp->name)
return 0;
/* a trust anchor exists with this name, RRSIGs expected */
if((a=anchor_find(env->anchors, dp->name, dp->namelabs, dp->namelen,
dclass))) {
if(a->numDS == 0 && a->numDNSKEY == 0) {
/* insecure trust point */
lock_basic_unlock(&a->lock);
return 0;
}
lock_basic_unlock(&a->lock);
return 1;
}
/* see if DS rrset was given, in AUTH section */
if(msg && msg->rep &&
reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_DS, dclass))
return 1;
/* look in key cache */
if(env->key_cache) {
struct key_entry_key* kk = key_cache_obtain(env->key_cache,
dp->name, dp->namelen, dclass, env->scratch, *env->now);
if(kk) {
if(query_dname_compare(kk->name, dp->name) == 0) {
if(key_entry_isgood(kk) || key_entry_isbad(kk)) {
regional_free_all(env->scratch);
return 1;
} else if(key_entry_isnull(kk)) {
regional_free_all(env->scratch);
return 0;
}
}
regional_free_all(env->scratch);
}
}
return 0;
}
int
iter_msg_has_dnssec(struct dns_msg* msg)
{
size_t i;
if(!msg || !msg->rep)
return 0;
for(i=0; i<msg->rep->an_numrrsets + msg->rep->ns_numrrsets; i++) {
if(((struct packed_rrset_data*)msg->rep->rrsets[i]->
entry.data)->rrsig_count > 0)
return 1;
}
/* empty message has no DNSSEC info, with DNSSEC the reply is
* not empty (NSEC) */
return 0;
}
int iter_msg_from_zone(struct dns_msg* msg, struct delegpt* dp,
enum response_type type, uint16_t dclass)
{
if(!msg || !dp || !msg->rep || !dp->name)
return 0;
/* SOA RRset - always from reply zone */
if(reply_find_rrset_section_an(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_SOA, dclass) ||
reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_SOA, dclass))
return 1;
if(type == RESPONSE_TYPE_REFERRAL) {
size_t i;
/* if it adds a single label, i.e. we expect .com,
* and referral to example.com. NS ... , then origin zone
* is .com. For a referral to sub.example.com. NS ... then
* we do not know, since example.com. may be in between. */
for(i=0; i<msg->rep->an_numrrsets+msg->rep->ns_numrrsets;
i++) {
struct ub_packed_rrset_key* s = msg->rep->rrsets[i];
if(ntohs(s->rk.type) == LDNS_RR_TYPE_NS &&
ntohs(s->rk.rrset_class) == dclass) {
int l = dname_count_labels(s->rk.dname);
if(l == dp->namelabs + 1 &&
dname_strict_subdomain(s->rk.dname,
l, dp->name, dp->namelabs))
return 1;
}
}
return 0;
}
log_assert(type==RESPONSE_TYPE_ANSWER || type==RESPONSE_TYPE_CNAME);
/* not a referral, and not lame delegation (upwards), so,
* any NS rrset must be from the zone itself */
if(reply_find_rrset_section_an(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_NS, dclass) ||
reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_NS, dclass))
return 1;
/* a DNSKEY set is expected at the zone apex as well */
/* this is for 'minimal responses' for DNSKEYs */
if(reply_find_rrset_section_an(msg->rep, dp->name, dp->namelen,
LDNS_RR_TYPE_DNSKEY, dclass))
return 1;
return 0;
}
/**
* check equality of two rrsets
* @param k1: rrset
* @param k2: rrset
* @return true if equal
*/
static int
rrset_equal(struct ub_packed_rrset_key* k1, struct ub_packed_rrset_key* k2)
{
struct packed_rrset_data* d1 = (struct packed_rrset_data*)
k1->entry.data;
struct packed_rrset_data* d2 = (struct packed_rrset_data*)
k2->entry.data;
size_t i, t;
if(k1->rk.dname_len != k2->rk.dname_len ||
k1->rk.flags != k2->rk.flags ||
k1->rk.type != k2->rk.type ||
k1->rk.rrset_class != k2->rk.rrset_class ||
query_dname_compare(k1->rk.dname, k2->rk.dname) != 0)
return 0;
if( /* do not check ttl: d1->ttl != d2->ttl || */
d1->count != d2->count ||
d1->rrsig_count != d2->rrsig_count ||
d1->trust != d2->trust ||
d1->security != d2->security)
return 0;
t = d1->count + d1->rrsig_count;
for(i=0; i<t; i++) {
if(d1->rr_len[i] != d2->rr_len[i] ||
/* no ttl check: d1->rr_ttl[i] != d2->rr_ttl[i] ||*/
memcmp(d1->rr_data[i], d2->rr_data[i],
d1->rr_len[i]) != 0)
return 0;
}
return 1;
}
/** compare rrsets and sort canonically. Compares rrset name, type, class.
* return 0 if equal, +1 if x > y, and -1 if x < y.
*/
static int